Liquefied gas circuit interrupters



Sept 22 1964 w. M. LEEDS ETAL 3,150,245

LIQUEFIED-GAS CIRCUIT INTERRUPTERS Filed Sept. 13, 195'? 4 Sheets-Sheet l Winthrop M. Leeds BY MMM.

ATTRNEY Sept. 22, 1964 w. M. LEEDS ETAL. 3,150,245

LIQUEFIED-GAS CIRCUIT INTERRUPTERS Filed Sept. 13, 1957 4 Sheets-Sheet 2 Sept. 22, 1964 w. M; LEEDS ETAL LIQUEFIED-GAS CIRCUIT INTERRUPTERS 4 Sheets-Sheet 5 Filed Sept. 13, 1957 mgm/@ NN. m

Sept. 22, 1964 Filed Sept. 13, 1957 W. M. LEEDS` ETAL LIQUEFIED-GAS CIRCUIT INTERRUPTERS 4 Sheets-Sheet 4 United States Patent O 3,150,245 LIQUEFIED-GAS CIRCUIT INTERRUPTERS Winthrop M. Leeds, Forest Hills, and Benjamin P. Baker,

Monroeville, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Vlennsylvarnla Filed Sept. 13, 1957, Ser. No. 683,760 2l) Claims. (Cl. 200-145) This invention relates to circuit interrupters in gen eral and, in particular, to liquefied-gas circuit interrupters.

A general object of the invention is to provide a circuit interrupter of more compact size and of Ya highly efiicient construction, which will render Iconsiderably improved operation over the conventional types of circuit interrupters, as disclosed in the prior art.

As Well understood by those skilled in the art, for decades of `years various forms of compressed-gas circuit interrupters have been designed, constructed and operated on electrical systems. These compressed-gas circuit interrupters have varied all the Way from early simple types of putter devices, to the modern high-speed, compressedegas circuit interrupter, whose gas reservoir chamber may contain pressurized gas at pressures of 500 pounds per square inch and upwards. It is, of course, obvious that the use of such compressed gasat such high pressures necessitates a large enclosing reser- Voir tank of adequate strength, which results in considerable expense and the use of large amounts of highstrength material.

It is proposed in the present invention to provide a new and improved circuit interrupter of a radically different type of construction. It is proposed to utilize circuit interrupters employing liqueed gas as the interrupting medium. This has the distinct `advantage of reducing the size of the circuit interrupter, and perhaps more importantly, enabling the use of an operating mechanism of less powerful design, and hence, of considerable reduced size.

It is proposed to use a circuit interruptor employing a liquefied gas instead of merely compressed gas, so that the inherent latent potential energy of the liquefied gas may be employed. Thus, it is not necessary to compress the gas at the moment of `arc interruption as is customary in they mechanically-operated pufter type of compressedgas circuit interrupters. In addition, it is not necessary to utilize a large pressure reservoir, where compressed gas is stored, as is customary in the ordinary type of compressed-gas circuit interrupter. Instead, it is proposed to utilize suitable gas in liquefied formr utilizing thereby the inherent latent potential energy of such liquefied gas, so that upon injection into the arc stream the heat of the arc Will elect a vaporization, or a gasification of the liquefied gas. Thus, the reservoir for the liquefied gas may be of considerably reduced dimensions, and the entire'circuit interrupter may be of considerably smaller size. Moreover, following the use of such liquefled gas for circuitvinterruption, it may subsequently function as a dielectric medium, in gaseous form, Within the circuit interruptor to reduce the spacing between conducting parts at opposite potential. As a result, the liqueed gas may be used for two purposes, first` to effect circuit interruption of the one or more arcs-drawn'during the interruption process, and secondly, as a" gaseous dielectric medium, under pressure, to permit close spacing of the several component parts. of the interruptor, and

. hence, bring about a drastic reduction in the overall dimensions ofthe circuit interrupterv employing the principles ot the present invention.

In United States Patent 2,757,261, issued July 31,1956,

and `assigned to the assignee of the instant application,

the surface of a liquefied gas, so that the latter may be employed at high pressure for injection into the arc 3,150,245 Patented Sept. 22, 1964 Ice there is disclosed and claimed the use of sulfur hexauoride gas as an interrupting medium. Also, in United States Patent 2,733,316, issued January 3l, 1956, to the same assignee, there is disclosed and claimed, the use of selenium hexaiiuoride, which also is an interrupting medium of unusual properties. It is proposed here in the present invention, to utilize these and certain other gases in a liquefied form.

As will be more apparent hereinafter, the present invention is not conned to the use of liqueed SFS or Sel-T6, which have demonstrated unusually effective interrupting performance, but the present invention broadly contemplates the use of other liquefied gases, that is, gases which can be liquefied at reasonable pressures at normal atmospheric temperatures. Naturally, however, the present invention excludes those gases which are not suitable for circuit interruption, or which have extremely poor dielectric properties. The present invention is conned to the use of gaseous mediums, which may be used to effect circuit interruption, and which gaseous mediums can be employed in a liquefied form. Examples of such other gases, which are liquefiable and are good circuit interrupters (though not as good as SP6 and SeF), and hence which may be used for certain applications, are carbon dioxide CO2, sulfur dioxide SO2, thionyl fluoride SOFZ, perfluoro'outane C21-i6, octo-fluoropropane C3138, dichlorodiiluoromethane CCl2F2, trilluorochloromethane CCIFS, triuorobromomethane CFaBr, and perchloryllluoride ClOaF. Y

The work or energy required to liquefy any of the liquetiable gases set out in the preceding paragraphs is released from the liquefied gas upon its injection into the arc stream. Thus, it is unnecessary to depend upon a heavy putter operating mechanism to effect rapid compression of a gas immediately prior to its injection into the arc, as disclosed in the prior -art devices. ture of the invention is very important for high current interrupters, as it is desirable to eliminate the necessity for providing the required heavy operating mechanism for the rapid compression of a large quantity of gas required for injection into high' power arcs.

By an y'application of the principles of the `present invention, one may utilize the Work or energy put into the liquefied gas, during the process 'of liquecation thereof, in the ultimate circuit interrupter installation, so that only a light operating mechanism may be employed; and the overall dimensions of the resulting circuit interrupter lmay be at aminimum.

An object of the present invention is to provide an improved circuit interrupter in which a liquefied gas is injected into the arc stream in an improved manner.

Yet another object of the present invention is to provide an improved circuit interrupterin which the arc is established closely adjacent to a place Where liquefied gas may be injected, so that the liquid will not have a chance to assume its lgaseous form priorto injection into the arc stream, Which Would-be the case if a considerable distance existed from the point of injection into the arc stream.

Still a further object of the present invention is to provide improved means for maintaining a relatively high liquid pressure during low-temperature ambient operation of a liquefied gas circuit interrupter. f Still a further object of the present invention is to provide a suitable gas for maintaining pressure upon stream.

Still a further object of the invention is to provide a mechanical piston-type impulse driving means for forcingliquefied gas at high pressure toward the arc zone.

This feal .E Another object'is to provide an improved circuit interrupter utilizing a liquefied gas, in which the liquid maybe injected into the arc stream for circuit interruption, and the vapor pressure over the liquid surface may be employed for effecting operation or the contact operating means.

Another object Vof the invention is to provideV anl improved circuit interrupter in which the arc is established in a pool of the liquefied gas. In certain applica-l tions, an interrupting structure may be situated at least partially in the pool of the liquefied gas, so as to enable a more efective interrupting operation to be obtained.

Still a further object of the invention is to provide an improved circuit interrupter utilizing a heating means for maintaining the vapor pressure of the liquefied gas at a level suitable for maintaining the liquefied gas under suliicient pressure for proper injection into the arc stream for Vefficient circuit interruption.

Yet another object of the invention is to employ a current-responsive master valve in the liquid line leading from the liquid reservoir to the interrupting zone.

Still a further object of the invention is to provide an improved operating means for synchronizing the injection 'of the liquefied gas into the arcing zone with the movement of the movable contact structure,

It is to be clearly understood that the present invention contemplates the injection of the liquefied gas into the arcing zone, as distinguished from interrupting devices `which may utilize a remote source of gas under pressure, which source itself may contain a gas in equilibrium with its liquid phase. Y

As set out above, U.S. Patent 2,757,261 discloses and claims the use ofV gaseous SP6 as an arc-extinguishing medium. There have been utilized many structures designed for the specific use of SF6 gas as the interrupting medium. In practically all cases, an effort has been made to prevent the gas Yfrom 'changing to a liquid, which condition depends upon both temperature and pressure.

In Vthe present invention, we propose the use of SFB liquid, or a mixture of SF@ liquid, vapor and gas as the linterrupting medium. We are not limiting ourselves to the use of the liquid as the interrupting medium, in that we propose to inject the liquid into the arc stream, where it may be converted into a vapor or a gas, even before it'reaches the high-temperautre conducting are. The general idea is that We propose to inject into the arc stream SFGV in some form, at a measuredor metered rate, comparable to optimum arc interrupting effectiveness, and allow the interaction of the end products and arc to follow the normal course.

As set out above, 1t 1s desiredto claim the above advantages when using other liquefied gases, since other.

gases can be used if they can be liqueed at reasonable Y pressures at normal atmosphericV temperature.

We have observed that when aV l" diameter vcylinder 7 long, filled with CFG gas at 60 p.s.i'.g. is discharged through a 50,000 ampere-arc at the rate of its total contents in l1/2 cycles, successful interruption is obtained. This is equivalent to approximately 12 cubic inches of liquid SFB for operation at normal temperature,.or a rate of about 8 cubic inches per cycle, which should lbe suincient if properly synchronized with the arcing period. It is another object of the invention to, utilize a liquefied gas v-in-accordance with Vthe foregoing experimental discovery.

Futher :objects and advantageswill readily become apparent upon .reading the following specification, taken in conjunction with the drawings, in which: A

FIGS. l-3 somewhat diagrammatically indicate various orifice forms which maybe employed in conjunction with,

'CII

contact structure being illustrated in the partially opencircuit position;

FIG. 5 is a fragmentary, enlarged, vertical sectional view through a portion of the circuit interrupter of FIG. 4, illustrating, to an enlarged scale, the injector or impulse piston and the relief valve, with the Contact structure being shown in the Vpartially open-circuit position;

FIG. 6 is a fragmentary, diagrammatic view illustrating -how the impulse piston may be mechanically connected Iwith the operating mechanism for the movable contact structure, so that liquefied gas is injected into the arc stream during the circuit opening operation;

FIG. 7 is a diagrammatic view illustrating an alternative method of maintaining the pressure upon the liquefied gas to a sufiicient level, so that it may be injected into the arc stream over a Wide range of ambient temperature conditions, the contact structure being fragmentarily shown in the partially open-circuit position;

FIG. 8 is a fragmentary, diagrammatic view illustrating another method for maintaining the liquefied gas at a suitable pressure, and in addition, utilizing the vapor pressure for effecting Contact operation;

FIG. 9 is a vertical sectional view of a modified type of circuit interrupter employing a pool of liquefied gas, with the contact structure being shown in the partially opencircuit position; and Y FIG. l0 shows still another modified type of circuit interrupter with the contacts in the partially open-circuit position. j Y Referring to the drawings, and more particularly to FIGS. l-3 thereof, it will be kobserved that a movable contact 1 makes cooperable engagement With a relatively stationary contact 2 interiorly of a surrounding orifice structure, generallyV designated by the reference numeral 3. In FIG. 1the stationary contact 2. is shown provided with'a hollow passage 2u, through which a liquefied gas, such as liquid SF, passes under pressure. The liquefied gas is injected into the arcing region 4, and the lines 5 indicate the relative position of the arc. It Will be observed that the arc 5, established between the separated contacts 1, 2, is extinguished by the entering stream of liquid SF6 passing through the tubular stationary contact 2. Naturally, the high temperature' conducting arc 5 vaporizes, or gasiies the entering liquid SFB stream with the resulting gaseous SFG exhausting around the movable contact'l as indicated by the arrows 6. The orifice structure 3 in the interrupting arrangement of FIG. l includes a tubular insulating member 7 of polytetraiiuoroethylene or polychlorotrifluoroethylene, having a centrally located restricted orifice portion, through which the arc 5 is drawn, and into which the liquefied SFS is injected.

FIG. 2 shows a somewhat similar arrangement in which, instead of the stationary contact 2 being tubular, a surrounding conducting ring-shaped guide member 9 is provided, having radially inwardly extending injector passages 10 provided therein. The injector passages l0 communicate with an annular manifold 11, which in turn isY connected to an entering inlet tube 12. The inlet tube 12 `is connected, in turn, to a source of a suitable liquefied gas, such as SFS, SeF or one of the previously mentioned liquefied, gases. With further reference to FIG. 2, it will be noted that here the arc 5 is established centrallyalong the orifice portion ofthe orifice member 7, with the entering liquefied gas I3 passing thereabout longitudinally through the orifice to exhaust about the movable contact ll in the manner indicated by the arrows lift. t t

Attention may now be directed to the modified orifice structure l5, illustratedtin FIG. 3, wherein aplurality of radially inwardly extending inlet passages I'are provided-communicating with a surrounding, annular-shaped kof the drawings.

in a single plane, so long as there are a suiiicient number of them to prevent the arc from finding a position in the ^oriiice where it cannot be sprayed with the incoming liquefied gas 13 strikes the arc column 5 generally transy versely thereof, circumferentially thereabout, and exhausts about the movable contact 1, asindicated by theY arrows 14. It willbe observed that in all of the orifice structures, illustrated in FIGS. l-3, that the entering liqueiied gas T13 is elfectively directed into the arc column 5, and mainture of liquid, vapor and gas will be converted into an interrupting effort by the heat absorbed from the arc 5.

It will be apparent that since the pressure in the circuit interrupter of our invention may be only 45 p.s.i.g. for normal insulation, and since this pressure may rise to 150 p.s.i.g. in the arcing area during the life of a high current are, the pressure developed in the injecting system should preferably be 300 or more p.s.i.g. The vapor pressure of SFB is 300 p.s.i.g. at about 70D F. As the temperature rises to 150 F., which should be the maximum operating temperature,` the vapor pressure will reach 700 p.s.i.g. Also, if the ambient temperature falls to 25"` F., the vapor pressure will drop to 150 psig., which is the pressure in the arc area into which the SFS is to be discharged. Therefore, at low ambient temperatures some means of maintaning injecting pressure must lbe employed.

To accomplish the maintaining of an adequate injecting pressure, it is proposed to employ the following methods:

(l) The use of a mechanically operated impulse device for measuring the fluid and forcing it into the arc path, as shown in FIGS. 4 and 5 lhereinafter described,

(2) The use of an accumulator with a gas, suchas nitrogen N2, in one end and sulfur hexafloride in the other, as illustrated in FIG. 7, hereinafter described.

(3') The use of SP6 and a heater to maintain the temperature of the container at or above some suitable value, such as 70 F., as shown in FIG. 8, hereinafter described.

With 'referenceV to FIGS. 4-6, which illustrate the first method using a mechanical injection device, it will be observed that the circuit interrupter, generally designated by the reference numeral 21, includes an upstanding reservoirA 22 containing, in this particular instance, SFS in the liquid phase, as indicated by the reference numeral 23, in equilibriumwith the vapor phase of SF, as indicated by the reference numeral-2.4. The meniscus betweenthe liquid and vapor phases 23, 24 is represented by the reference numeral 25f It willV be noted that the vapor pressure withinthe reservoir 22 will vary from 20 p.s.i.g. to 700v p.s.i.g. as the ambient temperature about the circuit interrupter. 21 variesfrom 1-40 F. to +150"` F.

Thelower end 27 of the reservoir 22 leads into an impulse piston device, generallyfdesignated bythe reference numeral 28, and` more clearely shown in FIG. 5 With reference toFIG. y5, it will be observed that an impulsepiston 29` is carried at the end of a piston rod 30, the latter passing throughan opening V31 provided at the left-hand end of anoperating cylinder 32. The impulse piston 29 contains a plurality of apertures 33 therein, which are controlled by a ringshaped, check-valve plate 34 carried on a pin 35 extending outwardly from the piston rod 30.

Thus, upon rightward, driving movement of the piston rod 30 during the opening operation of the interrupter 21, the valve plate 34 will close the openings 33 in the impulse piston 29, to thereby place the liquid SFS Within the region 36 under a very high pressure, such, for example, as 1200 p.s.i.g. Upon the return closing movement of the piston rod 30, the valve plate 33 Willuncover the apertures 33 to permit the region 36 to lill again with liquid from reservoir 22 preparatory for the next opening operation of the interrupter.

With further reference to FIG. 4, it Will be noted that the impulse piston device 2S is located at the ground flange support 37 of a condenser bushing, generallydesignated by the reference numeral 38, and including a pair of oppositely extending, porcelain shells 39, 40 placed under compression by any suitable means, not shown. The ground flange support 37 is supported at the upper end of an upstanding framework 41, which may be formed from angle-iron supports.

The condenser bushing 38, in addition, includes a centrally disposed core 42, which may be formed from a Wrapping of a paper-like material having conducting foils interspersed therein, to form the condenser layers for the bushing 38.

A terminal stud 43 extends longitudinally through the core 42, and is connected at its right-hand end, by a flexible connector 44, to a movable contact 45. The movable contact 45 is carried by an upstanding support 46, the `latter being carried by a pair of longitudinally extending, insulating, operating rods 47. The pair of operating rods 47 are pivotally connected, asV by means of pins 4S, with insulating actuating rods 4S, the latter being pivotally connected, as at 50, to anA actuating crank 51. The crank 51 rotates about a iixed center 52, and has an external crank arm 53. The shaft 52 interconnecting the crank arms 51,` 53 makes a gas-tight sealing connection with a casing 54. This shaft seal may ass-urne the `form as illustrated and claimed in US. patent application SN. 576,875, tiled April 9, 1956, by Harry J. Lingal, and assigned to the assignee of the instant application.

Certain features of the interrupter 21 are described and claimed in United States patent application filed December 6, 1957, S.N. 701,226, by Benjamin P. Baker and assigned to the assignee of the instant application.

Cooperable with the two movable contacts 45 is a pair of stationary contacts 55, supported by upstanding brackets 56 from aninteriorly disposed insulating tube S7. The insulating tube 5'7 is disposed interiorly of a surrounding, tubular, weatherproof casing 58, made of any suitable Weatherproof material, such as porcelain.

The right hand end of the porcelain casing 58, as viewed in FIG. 4, may be supported from an end plate 59, the latter being supported at the upper; end of an insulator column 60.

An enclosing end cap 61 is provided with an overpressure valve 62, biasedto the closed position by a coiled spring 63, and arranged to open upon excessive pressure within the'region 64 within casing 58.

Situated adjacent the contacting ends or" the stationary contacts S5 are orifice structures 3, which may assume the form set out in FIGS. 1-3 of the drawings. As more particularly illustrated in FIG. 5 of the drawings, the

orifice structure 3 assumes the form shown inFIG 2f The inlet tube 12 leading to the orifice structures `3, as shown in FIG. 5, communicates with a relief valve, generally designated by the reference numeral 65. With reference to FIG. 5, t-will be noted thatthe relief valve 65 includes aivalve 66, biased by a spring 67over a valve seat 65, communicating with an inlet tube 69. The inlettube 69 leads to the operating cylinder 32.

A compressor 71 recompresses the gaseous fluid, such Vas gaseous SF6 in the region 64 within casing 58, and

The crank arm 53 is pivotally connected, as at 75,

to a vertically extending, insulating, operatmg rod 76, the latter being connected to any suitable external operating mechanism,'located, preferably, at ground potential. YThe Vinsulating reciprocaily movable, upstanding, operating rod 76, in addition, is pivotally connected, as at `77, to a bell-crank lever 78, the latter being rotatable about a fixed shaft 7 9, as more clearly shown in FIG. 6 of the drawings. The upper end of one arm Si) of the bell-crank lever 7S is pivotally connected by a slotted connection, as at 81, to the left-hand end of the piston 4rod 30.

The operation of the circuit interrupter 21 will now be described. In the closed-circuit position of the interrupter 21, the electrical circuit therethrough extends from the terminal 82, through the centrally disposed terminal stud 43, through flexible connector 44 to the left-hand movable'contact 45. The circuit then extends through the left-hand stationary contact 55, through exible connector 33 t-o the right-hand movable contact 45. The circuit continues by way of the righthaud stationary Contact S5, through a flexible connector 84 to conducting end plate 59. The circuit passes from end plate 59 tothe conducting closure cap 61 to a line terminal stud 8S, to which the external line connection may be made.l

Y When it is desired to effect the opening operation of the circuit interrupter 21, suitable operating mechanism, not shown, connected to the insulating operating rod 76, effects downward opening motion of the same. The downward movement of the operating rod 76 effects, Vthrough the crank arms 51, 53 leftward movement of the insulating rod 49 and hence of the operating rods 47. The insulating operating rods 47 being connected to the two movable contacts 45, by way of the upstanding supports 46, causes leftward separating, opening motion of the contacts 45 away from the two stationary contacts 5S, drawing a pair of serially related .arcs 86,87 therebetween.

The downward movement of the operating rod 76 also effects through the bell-crank 78 (FIG. 6) rightwarcl driving movement of the piston rod 30, yand hence of the impulse piston 29. This will cause a forcing, or driving of liquid SP6 through the inlet tube 69 to the two relief valves 65, where, upon the attainment of adequate pressure, say ofthe order of 1200 p.s.i.g., the pressure will uncover the valve seats 68, and permitliquid SFS to pass through the inlet tubes 12 into the annular manifolds 11, through the inlet tubes 12 into the annular manifolds 11, through inlet or injecting passages 10 and into the arcs 86, S7, in the manner illustrated in FIG. 2, of the drawings.

, By way of example only, and not by way of limitation, considering SP6 as the interrupting medium, the pressures throughout the interrupter 21 may conceivably be as follows: pressure in region 64, throughout the interior of porcelain casings 39, 40 and Y5S, 45 p.s.i.g.; pressure in the inlet tube 69, 1200 p.s.i.g.; pressure in the manifold 11, 400 p.s.i.g.; pressure about the tip of the moving contacts 45 adjacent the orifice structuresrS, 60 p.s.i.g.; and pressure in the arcing space, 150 p.s.i.g. The vapor pressure in carries the movable contacts 45 to their closed position in engagement with the stationary contactsSS, completing the electrical circuit through the interrupter 21. The upvward movement of the operating rod 76 effects, through the bell-crank 78 (FIG. 6), leftward recharging movement of the piston rod 3ft and impulse piston 29, the

ycheck-valve plate 34 uncovering the aperture 33, and

causing a measured quantity of liquid SFB to be admitted l' into the region 36 within operating cylinder 32.

Thus, FIGS. 4-6 illustrates a mechanical injector type of device adapted to a bushing-type circuit breaker 21, in which the SFS container 22 is mounted at ground potential and labove the level of the interrupters 3. An insulating tube 69 leads from the container 22 to the interrupting elements 3, which may be as shown in FIGS. l, 2 or 3. The tube 69 terminates in the interrupters 3, as shown. The impulse injector 28 `and the high-pressure relief valves 65' are located in the line 69 between the SP6 container 22 and the interrupters 3. The relief valve 65 should be near the interrupters 3 and may be set to open at 800 p.s.i.g. The injector 28, designed to deliver 1200 p.s.i.g., may be located any place in the line 69 if there is no place where gas pockets can form between lthe injector 2S and relief valve 65. Lower injector pressures may be used if the relief valves are of a type that requires a high pressure to open, and :a lower differential pressure to keep open. The injector piston 29 is mechanically connected directly to the operating mechanism, which operates the contacts 45, 55. The piston 29 may carry a check valve 34 to speed up refilling on the closing stroke.

The entire structure is filled with SFS gas at approximately p.s.i.g. for insulation purposes, and the compressor 71 may take the gas at 45 p.s.i.g., drawing it through the lter 73 and deliquefying the gas. The compressoi- 71 may then force the reliqueiied SF@ through the Vdischarge tube 72 into the reservoir Z2, as shown in FIG.

Y 4 of the drawings.

the region 24 of the reservoir 22 may vary from 20 p.s.i.g.

l 51, 53 closing motion of the operating rods 47. -VThis FIG. 7 shows somewhat diagrammatically how an ac cumulator reservoir 88 can be used to maintain high- ,driving pressure even at low :ambient temperatures, where the SFS-would condense, or have low vapor pressure. In conjunction with a suitable Valve, this may be used to replace the mechanical injector, or impulse system shown in FIG. 5. As illustrated in FIG. 7, `an inlet valve, generally designated by the reference numeral 89, may include a Valve 90 biased by a compression spring 91 to the closed position over a seat 92, associated with an inlet feed tube 93. The valve 89 may be cam-operated through a cam surface 94 carried by one of the insulating operating rods 47.

During the opening operation, the cam surface 94 forces downwardly -a cam roller 95, carried by an arm 96 pivoted to a rotatable ram 97 and eiecting opening of the inlet valve 90. The inlet valve 89 may be so arranged that the cam 94 will not effect the opening of the inlet valve 90 during the closing stroke of the modified type of interrupter, generally designated by the reference numeral 98.

Thus, rightward closing movement of thel operating rods 47 and cam surface 94 will be ineffective to cause opening of the valveV 90, since during this movement the arm 96 'will rotate about its pivotal connection 99 with arm 97 against the opposition afforded by a tension spring 100.

, Preferably, to economize the use of the liquid SFB, a series-current control valve 101 is positioned inV inlet tube 93 to control thev opening Ythrough inlet tube 93 as a function of the magnitude of current being interrupted by the circuit interrupter 98. A cylinder 102 of nitrogen gas N2 under pressure is provided, controlled by f-a valve '193, to maintain a relatively high pressure in the space '104 above a mechanical, movablediaphragm 105 within accumulator reservoir 88. v

Y The liquid SFS may be disposed in the region 106 below diaphragm 10S, with SP6 gas in the space 107 above the 9 meniscus 103 separating the liquid and gas phase of the SFS.

The Walls of the reservoir 88 are provided with integrally formed stops 109, which limit the downward travel of the diaphragm 2.65. Also, a float 11d may be provided to` sound an alarm, and to block breaker operation if the liquid SFS should reach this minimum value.

Thus, FIG. 7 illustrates how a lsuitable valve i5@ may be used to replace the injector system 2li, shown in FIG. 4. The Valve 96 may be biased to the closing position by the spring 91 and opened by a oarn surface 9d attached to the Contact operating mechanism, so that the size of the pipe 93 or valve gli will determine the rate of use of the SFG and the time for the motion of the movable contact 45 will determine the amount of SF@ used. The cam 94 can be arranged so that the Valve will not be opened during the closing stroke.

A master valve lill may be used in series wit-h the foregoing inlet valve 39, the former being responsive to current so that smaller amounts of SFS will be used when interrupting small values of current.

With the arrangement shown in FIG. 7, the accumulator die takes the place of the mechanical injector 23 by above a ilexible piston or other diaphragm 165. The pressure exerted by the nitrogen is affected only moderately over this temperature range. However, the pressure does decrease as it expands in response to withdrawal of the SP6. In charging the accumulator for the iirst time, at say 70 F., nitrogen would be pumped in the top to 30() p.s.i.g. with the baille on the stop liti?. rl`hen, SP6 should be pumped in, as a liquid, until the nitrogen pressure is 700 psig. Normally diaphragm ldd will rest on the liquid face Idil and there-would be no SF@ gas above the liquid, though as the temperature rises to slightly above 150 F., some vapor may form above the liquid SP6 and the pressure asserted by the nitrogenwill increase slightly, if the temperature drops to a 40 F., the pressure asserted by the nitrogen will decrease a moderate amount, resulting from the temperature drop. If the liquid SFS is then used down near the stop im, the pressure will never drop much below 30G p.s.i.g. even thoughthe temperature may then drop to a -40 F. At any other intermediate point in .the SP6 liquid usage, temperature variations will only cause a change in the relative amounts of SP5 gas and liquid, but not appreciably elect the pressure.

The larger the iaccumulator 88, the more liquid SP6 Vmay be used without dropping the pressure below the permissible value. The larger the volume of nitrogen, the Vsmaller the variation in pressure as a function of both temperature and SF@ usage.

The inlet valve 9d should be located near the interrupter 3 so that any liquid discharged through the valve 9i) is` immediately available for arc extinction instead of lilling the tube between the valve @il and the lto that shown 1in FIG. 7 except that instead of using an accumulator 83, the SP6 is stored in areservoir lill, and heat is applied as necessary to the reservoir lll 'Into maintaina temperature of 70 l?. ornabove. ln this `case, the vapor pressure will never be less than 300 psig.

The heating coil M2 may be connected' to any suitable 4 electrical source and surrounds the reservoir 111. A

sump lll collects discharged SP6 gas from the interior of the interruptor, such as the discharge space 64 of FIG'. 4. From the sump 113 a compressor 7l may be utilized to reliquefy the gas, and to send it back through pipe 72 into the reservoir lll in the liquid phase.

lf the ambient temperature rises to 150 F., the vapor pressure of the SP6 in the space 24 will increase to 700 psig. as long asA there is still usable SFS liquid 23 to be vaporized in the reservoir 11i. As a result, the pressure operating range will be between 300 and p.s.i.g. regardless of the ambient temperature conditions.

it will Vbe observed, viewing FlG. 8, that a conduit 114 is connected to the upper end of therreservoir lll to the SF@ vapor space 2d.. An electro-magnetically actuated closing valve i115 is operated by energization of a closing coil A second heating coil ill7 surrounds a part of the conduit lill to maintain the temperature of the vapor within the conduit lid to at least the minimum temperature oi 76 F.

The lower end of the conduit 1M feeds into the lefthand end of an operating cylinder 1118, within which reciprocally moves a Contact piston M9. A piston rod 32d, connected to the operating piston 119 lat one end thereof, has the other end llZll connected tto a movable contact 45, not shown. An accelerating compression spring 122 bearing against a plate 123, affixed to the piston rod Mil serves to bias the piston rod i320, and hence the movable contact d5, to the open-circuit position.

The lower end of the conduit 114 is also connected to ya tripping valve 12S, which is electrically actuated by a tripping coil E26. A conduit 1.27 leads from the tripping valve :tI-*5 to the sump i115. If needed, a third heating coil 1.23 surrounds the operating cylinder 11S to maintain the temperature of the Sl vapor therein to the minimum 70 F. level.

The operation of the modified type of circuit interrupter 1F29 will now be described, with reference being had to the circuit interruptor @S of FIG. 7. Since the heating coils lli, lli', and 12S maintain the temperature of the liquid 23 and t e vapor 2d at the minimum 70 F. level, as mentioned, the pressure operating range will be between 30G and 760 psig. regardless ofthe surrounding ambient temperature conditions.

To eifect .the closing or" the interrupter 129, the closing coil llo may be ener ized, by any suitable con-trol, to thereby eect the opening of the closing valve 115. This will permit SFS vapor, from the vapor :space 24, to pass downwardly through the conduit 114 and into the operating cylinder 118, the opening tripping valve 125 remaining closed during this time. The entrance of SP6 vapor into the operating cylinder 11S, during such actuation of Vthe closing valve 115, will effect rightward, or closing movement of the operating piston 119. As a result, the piston rod 129 will e'te-ct closing of the movable contact 45, not shown, and, in addition charging of the opening,

accelerating compression spring 122. The contacts, being closed, will permit current to pass through the interrupter i299."

To effect the opening of the modied type of interruptor 129, the closing valve 115 is closed, and the opening, tripping Valve 125 is opened by the energization of :the tripping coil 126, This will discharge the SFS vapor under pressure within the lower end of the conduit 114 and the left-hand end of the operating cylinder 118 into the sump The opening, accelerating compression spring 122 'will then eltect the opening of the movable contact 45 (FIG. 7) and a suitable cam structure 94, as illustrated -in FIG. 7, will bring about the opening of a valve to eiiect arc extinction. The breaker may be closed by operating valve M5, latched closed, and the gas dumped by opening valve 3.25, in which the breaker will lbe opened in the usual `way'by unlatching a mechanism. The movable contact fi will move to its fully open-circuit position,

lled to the level 132 with liquid SFS 133.

the container 131 in a sealed manner.

as caused bythe spring 122, and the circuit interrupter 129 is in readiness for a subsequent closing operation.

It is to be observed that there are many important advantages of the structure described over other types of interrupters previously employed in the art. First, as disclosed in FlG. 8, there is a light operating mechanism for the contacts. Secondly, the valve 90, controlling the flow of liquid SFS, opens and closes, being controlled by motion `of the movable contact 45. Thirdly, the discharge gas is cleaned and pumped back into the high-pressure system. the contacts, as shown in FIG. 8, thus not requiring a separate hydraulic system.V Fittlrly, a large number of opershown, in that the master valve 101, in series with the current passing through the interrupter, is responsive to fault current, so that the full amount of liquid SFS is used only for heavy-fault current interruption. Seventh, the dielectric strength of the SFS medium is proportional to its density (temperature and pressure). Since the back pressure is iixed by `the arc history, andthe temperature is a Ifunction of evaporation, dielectric strength should develop rapidly after arcing or as the current decreases.

An eighth advantage ofthe structures shown is that smaller and lighter porcelains Vand associated parts may be used, since large puters for compressing SP6 gas are not required. A ninth advantage is that when inspecting or servicing the interruptcrs, most ofV the gaseous SF, Within the interior breaker space 64 (FlG. 4), can be pumped and stored in the SFS liquid reservoir. A tenth advantage is that the amount or" liquid SFS used per interruption does not necessarily have to 1be metered, or measured accurately, as the excess will :be pumped back into the system, or blown into the atmosphere if operations are too'frequent. ln addition, it will be noted that a temporary elevation Vof the'pressure immediately following arc interruption will add to the dielectric strength, when it is most needed.

It `is .to be clearlyv understood that with reference to the foregoing structures, `the present invention is not limted by the previously recited dimensions, temperatures or pressures. These values were chosen for purposes of illustration, andare, therefore, Vnot applicable to all breaker ratings. Also, it is to be understood that although the invent-ion was illustrated in FIG. V4 as applied to a l single-bushing type of interrupter, it is equally aplicable to other types of breaker constructions, which may be similar to those generally lassociated with the compressedgas circuit interrupter art.

FIG. 9 shows a modified type of circuit interrupter 130 of a type. considerably different from the previously described structures. With reference to FlG. 9, it will be observed that there is provided a metallic container 131 The SFS vapor space 134 is at the upper end of the casing 131, as shown. Two bushings 135, 136 extend through opposite ends of The lower'bushing 136 accommodates a'terminal stud 137, to the upper end of which is .affixed a stationary contact 135.

Cooperable withthe stationary contact 138 is .a reciprocally movable, moving contact 139, which `slides in a `sealed manner, within the upperbllshing V135. The

upper end 140 of the movablecontact 139 may be con- Ynected to. any suitable external mechanism, not shown.

relaying operations.Also a current transformer may be Four-thly, the SFS vapor may be used to operate associated with the lower bus-hing for relaying convenience.

within the interrupting structure 142. The movable contact 139 moves longitudinally through the centrally disposed orices 146 provided by the several apertured plates 144.

It will be noted that the container 131 is filled with liquid SFS at such a pressure, so that at 150 F. the liquid level 132 will not fall below the top of the interrupting structure 142 The movable contact 139 is operated through a suitable gas-tight seal 147, and in the opencircuit position is disposed above the liquid level 132, as indicated by the dotted line 148.

The vapor pressure may vary from 20 p.s.i.g. at 40 F. to 700 p.s.i.g. at +150 F., without appreciably affecting the operability of the interrupter 130 or the dielectric strength of the space 134iy above the liquid level 132.

The interrupting structure 142 may consist of an insulating block with interstices, or pockets 145, through which the are 149 may be drawn. The heat of the arc converts the liquid to a gas, which blasts the are 149 as it passes through the oriiices 146.

In the closed-circuit position of the interrupter 13), the heat generated by the contacts 138, 139 carrying large values of current will vaporize a portion of the liquid SFS, which vapor will carry the heat to the upper part of Vthe chamber wall 131, Where the vaporized SF@ will be condensed and returned to the liquid body or pool, thus permitting lighter and less expensive current carrying parts.

From the foregoing description ofthe modied type of interrupter 130, illustrated in FIG. 9, it will be observed that we have produced a completely enclosed, small and compact breaker, with a large current-carrying capacity and having a large interrupting rating. VThis breaker, in addition, has a very long life and is highly effective in service.

It Wilhof course, be apparent that although the container 131 is disclosed as being of conducting material with bushings 135, 136 at eachV end, as shown, the container 131 may be made of an insulating material, and the bushings 135, 136 omitted.

Also, the moving contacts 139 may be located at the bottom and the arc drawn from the vapor at the upper end of the container 131 down into the liquid body or pool 133 itself. This may be preferable for large values of current, but possibly might be somewhat susceptible to restrlkes when interrupting leading currents.

FIG. l0 illustratesa modified type of liquid pool interrupter, generally designated by the reference numeral 151, utilizing the pressure generated at a pressure-generating arc 152 to force liquid SFS toward an interrupting are 153. Y

The pressure generating arc 152 is established between a stationary contact 13M andan intermediate contact 154, the latter being biased by a spring 155 toits open position.

The interruptingarc 153 is established between the intermediate contact 154 and the upper movable contact 139. rlhe interrupting structure 16@ consists of an enclosure 161 comprising a superimposed set of insulating plates, held compressed by tie rods, not shown. "One or more upper plates 163 provide orifices 164 through which the interrupting arc 153 is drawn. Arc ektnction occurs in a manner similarto that discussed in connection Wirth FIG. 9, with the exception' that here a serially-related pressure-generating arc 152 is drawn. The current transformer 141er here is mounted externally tothe casing 131 for the convenience of removal from the bushing V115. 1 Y Y From the foregoing description of the present invention, it will be apparent'that there are disclosed novel types of circuit interrupters utilizing liquefied gas injected into the arcing zone. Althoughliquefied SFS has been used as an example of a possible liquefied gas, in describing the structures, it is to bewclearly understood that liquefied selenium hexafiuoride, or any one or a mixture of two or more of the liquefied gases enumerated above in the objects of the present invention may be employed in substitution of liquid SP6.

The various gases hereinbefore enumerated which are suitable for use in interrupters of the type considered, have similar properties and characteristics as set out in the following table.

Although the foregoing liquefied gases may be used to advantage, exceptional and unusual performance is obtained with liquid SP6 and liquid SeF6, since the gaseous phase of these two materials are so highlyeffective in arc interruption and high dielectric insulation.

It is stressed that an important feature of the invention is that no powerful mechanism is required to effect sudden compression of a gas, since advantage is taken of the initial energy put into the liquefied gas during the initial liquefying operations. Although `the compressor 71 has been illustrated for .the purpose of effecting reliquefaction of the gas, this may be eliminated and the gas exhausted to atmosphere. It Will, of course, be apparent that if it is eliminated, the entire mechanical etiort required may be exceedingly light, having only to effect contact separation and valve opening for the admission of liquefied gas into the arcing zone.

Although the orifice structure of FIG. 2 of the drawings was applied to the circuit intermpters, 21, 93 and 129, it is to be understood thatthe orifice structure of either FIG. l or FIG. 3 could'be employed, instead of the orifice structure of FIG. 2.

it is furthermore to be noted that in the structure of the present invention, the interrupting arc is drawn immediately adjacent, and in close proximity to the point of injection of the liqueiied gas.

Although there have been illustrated and described various interrupting structures, it is to be clearly understood that the same were merely for the purpose of illustration,

" and that changes and modications may readily be made therein by those skilled in the art, without departing from the spirit and scope of the invention.

We claim as our invention: v

l. A fluid-blast circuit interrupter including a pair of separable contacts separable to establish an arc, an orifice member associated with one of said contacts to direct fluid flow into the arc, means deiining a manifold at least partially surrounding said orifice member, means providing an inlet opening to said manifold, means forforcing at least one liquefied gaseous fiuorine compound selected from the group consisting of SeF, SFS, SOF2, CZFG, C3F8, C103, CFgBr, CClZFZ, and CClF through said Vinlet opening and into the manifold, a plurality of inlet apertures spaced circumferentially around said orifice" member and extending through the same for feeding iiuid into the arc, and said inletapertures in addition extending axially of i4 said orifice member to disseminate the entrance flow of fluid into the arc stream.

2. A circuit interrupter including a metallic casing, said metallic casing included a pool of at least one liquefied gaseous iiuorine compound selected from the group consisting of Sel-J5, SFS, SOFZ, C2F6, CaFB, C1031?, CFSBr, CClgiiz, and CClFg, a pair of insulating bushings extending into opposite ends. of said metallic casing, a stationary contact carried adjacent the inner end of one of said bushings Within the pool of the liquefied gaseous iiuorine compound, a cooperable movable intermediate contact separable from said stationary contact to establish a pressure-generating are, a cooperable second movable Contact movable free of the pool of the liquefied gaseous fluorine compound in the fully open-circuit position, said second movable contact being cooperable with the movable intermediate contact to establish an interrupting arc, means for forcing fluid iioW from said pressure-generating arc toward said interrupting arc to assist in eecting extinction of the same, and said second movable contact being slidable Within the other of said bushings.

3. A circuit interrupter including a metallic casing, said metallic casing included a pool of at least one liquefied gaseous iiuorine compound selected from the group consisting of SeFS, SP6, SOF2, C2F6, C3138, ClOSF, CFSBr, CCIZFZ, and CClF3, a pair .of insulating bushings extending into opposite ends of said metallic casing, a stationary Contact carried adjacent the inner end of one of said bushings within the pool of the liqueiied gaseous iiuorine compound,r a cooperable movable intermediate contact separable from said stationary contact to establish a pressure-generating arc, a cooperable second movable contact movable free of the pool .of the liquefied gaseous fluorine compound in the fully open-circuit position, said second movable contact being cooperable with the movable intermediate contact to establish an interrupting arc, means definingan interrupting orice structure disposed adjacent said interrupting arc, means for forcing fluid flow from said pressure-generating arc into said interrupting orifice structure to assist in effecting extinction of the interrupting arc, and said second movable contact being slidable Within the other of said bushings.

t 4. A huid-blast circuit interrupter including contact' means for establishing an arc, operating means for actuating the contact means, compressed-duid reservoir means contaim'ng at least .one liqueiied gaseous fluorine cornpound selccted from the group consisting of SeF6, SP6,

S0132, CZFS, C3F8, ClOSF, CFSBr, CCl2F2, and CClF3,

means for maintaining said liquid at a sufficient driving pressure to enable it to be forced into the arc stream, said maintai-ningmeans including a different gaseous material under high pressure, conduit means interconnecting said compressed-duid reservoir means with said arc, blastvalve means responsive to the opening operation of said operating means for releasing a blast of liquefied fluid into the arc through said conduit means .to assist in effecting the extinction of the same, and a master control valve disposed in said conduit means responsive to the magnitude of the current being interrupted to control the amount of liquid passing throughV s'aidiconduit means, the master control valve functioning to permit more liquid to pass through said conduit means during heavy-current interruption than during light-current interruption.

5. A circuit interrupter including a metallic casing, said metallic casing included a pool of at least one liquefied gaseous fiuorine compound selected from the group consisting Of SSFS, SFS, Sol-72, C2F6, VC3138, C1031?, CFgBI, CC12F2, and CCH-73, a pair of insulating bushings extending into opposite ends of said metallic casing, a stationary contact carried adjacent the inner end of one of said bushings Within the pool of the liquefied gaseous fluorine compound, a cooperable movable intermediate contact separable-from said stationary contact to establisha pressure-generating are, a cooperable second movable contact 3,1 15 movable free of the pool of .the liquefied gaseous uorine compound in the fully open-circuit position, said second movable contact being cooperable with the movable intermediate contact to establish an interrupting arc, interrupting means for forcing fiuid flow from said pressuregenerating arc toward said interrupting arc to assist in effecting extinction of the same, said interrupting means defining a plurality of spaced orifices through which the interrupting arc is drawn, and said second movable contact being slidable Within the other of said bushings.

6. A circuit interruptor including a metallic casing, said metallic casing included a poolV of at least one liquefied gaseous fluorine compound selected from the group Consisting Of SFG, SFS, S0132, CZFG, CSFS, C103, CFgBl, CCl2F2, and CCH-T3, a pair of insulating bushings extending into opposite ends of said metallic casing, a stationary contact carried adjacent the inner end of one of said bushings Within the pool of the liquefied gaseous fiuorine compound, a cooperable movable intermediate Contact separable from said stationary Contact to establish a pressuregenerating arc, a cooperable second movable contact movable free of the pool of the liquefied gaseous fiuorine compound in the fully open-circuit position, said second movable contact being cooperable with the movable intermediate contact to establish an interrupting arc, means Ydefining an interrupting orifice structure disposed adjacent said interrupting arc and Wholly supported by the inner end of said one bushing, means for forcing fiuid flow from said pressure-generating arc into said interrupting orifice structure to assist in effecting extinction of the interrupting arc, and said second movable contact being slidable Within the other of' said bushings.

7. A fiuid-blast circuit interrupter including contact means for establishing an arc, operating means for actuating the Contact means, compressed-fluid reservoir means containing at least one liquified gaseous fiuorineV compound selected from the group consisting of Sel,V SP6, S0152, CgFG, CSFB, ClO3F, CF3BI`, CClgFg, and means for maintaining said liquid at a sufiicient driving pressure to enable it to be forced into the arc stream, said maintaining means including a different gaseous material under high pressure, conduit means interconnecting said compressed-huid reservoir means with said are,

said operating means including a cam, cam-operated blastvalve means responsive to the opening operation of said loperating means and said cam for releasing a blast of liquefied fiuid into the arc through said conduit means to assist in eiiecting the extinction of the same, andv a master control Valve disposed in said conduit means responsive to the magnitude of the current being interrupted to control the amount of liquid passing through said conduit means, the master control valve' functioning to permit more liquid togpass through saidconduit means during heavy-current interruption than during light-current interruption. 1

8. .A fluid-blast circuit interrupter including a pair of separable contacts separable to establish an arc, one of said contacts Abeing relatively fixed, an orifice member surrounding said one contact and extending away from ythe face Vthereof to direct fiuidrfiow intoV the arc, means Adefining a manifold at least partially surrounding said orice'member, rmeans providing an'inletopening to said manifold, means'for forcing :at least one liquefied gaseous fiuorine'compound s'electedfrom the group'rconsisting of S6126, SFS, SOFVQCZFGQCIFg, C103?, CFgBI', CCIZFZ, and

Y CClF3 through said inlet Qpening and intothe manifold, a plurality'of (inlet apertures spacedfcircumferentially around said ori ficel member and extending through the same forY feeding fiuid into the arc, and 4said inlet apertures in addition extending axially Vof said orifice member to disseminate the entrance fiovv offiuid'into the 'arc stream. A t 1 t' 9.'A A circuit interrupter including a metallic casing, said metallic casing included a pool ofV at least one liquefied gaseous fiuorine compound selected from the group con- Stating or sans, SFB, song, Cms, c3118, Close, Caer, CCl2F2, and CClF3, a pair of insulating bushings extending into opposite ends of said metallic casing, a stationary contact carried adjacent the inner end of one of said bushings Within the pool of the liquefied gaseous ffuorine compound, a cooperable movable intermediate contact separable from said stationary Contact to establish a pressuregenerating arc, a cooperable second movable contact movable free of the pool of the liquefied gaseous fluorine cornvpound in the fully open-circuit position, said second movable'c'ontact being cooperable with the movable intermediate contact to establish an interrupting arc, interrupting means for forcing fluid flow from said pressuregenerating arc toward said interrupting arc to assist in effecting extinction of the same, said interrupting means including a plurality of contiguously-disposed insulating plates dening spaced orifices for said interrupting arc, and said second movable contact being slidable within the other of said bushings.

10. A circuit interrupter including a metallic casing, said metallic casing included a pool of at least one liquefied gaseous iiuorine compound selected from the group consisting of SeF, SP6, SOF2, C21-" 6, C3158, ClOaF, CF3Br, CC12F2, and CClF3, a pair of insulating bushings extending into opposite ends of said metallic casing, a stationary contact carried adjacent the inner end of one of said Vbushings within the pool of the liquefied gaseous fiuorine compound, a cooperable movable intermediate contact separable from said stationary contact to establish a pressuregenerating arc, a cooperable second movable contact movable free of the pool of the liquefied gaseous fluorine compound in the fully open-circuit position, said second movable contact being cooperable with the movable intermediate contact to establish an interrupting arc, means at least partially of insulating material defining a pressure-generating chamber and a communicating interrupt- Y ing orifice structure disposed adjacent said interrupting arc, means for forcing fluid flow from said pressure-generating arc into said interrupting orifice structure to assist in effec-ting extinction of the interrupting arc, and said second movableycontact being slidable Within the other of said bushings.

l1. A fluid-blast circuit interrupter including contact means for establishing an arc, operating means for actuating theV contact means, compressed-fluid reservoir means containing at least one liquefied gaseous fiuorine compound selected from the group consisting of SeFG, SP6, SOFg, CZFS, C3F3, C103F, CFgBI', CCIZFZ, and CClFg, means for maintainingsaid liquid at a sufficient driving pressure to enable it to be forced into the arc stream, said maintaining means including a different gaseous material under high pressure, conduit means interconnecting said compressed-fluid reservoir means with said arc, said operating means including a cam, cam-operated vblastvaive means responsive to the opening operation of said operating means and said cam for releasing a blast of liquefied fiuid into the arc through said conduit means to assist in effecting the extinction of the same, means 'rendering said cam ineffective during a closing operation,V and a master control valverdisposed in said conduit means responsive to the magnitude of the current being interrupted to control the amount of liquid passing through said conduit means, the master control valve functioning to permit more liquid Vto pass through said conduit means during heavy-current interruption than during lightcurrent interruption.

- l2. A fluid-blast circuit interrupter including a pair of separable butt contacts separable to Vestablish an arc, an orifice member associated with one of said butt contacts to direct fiuid flow into the arc, means defining'a mani- `fold at least partially surrounding said orice member,

C Cl2F2, and CCIP-g throughsaid-inlet opening andinto the manifold, a` plurality of' inlet apertures spaced; circumferentially around-saidl orifice rnernber` and extending throughdhe same .fopfeedingmuidfinto the arc, and V'saidf inlet apertures ,inaddition extendingaxially of said orifice member toA disseminate. theentrance qW. .of iiuid` intothe arc. stream.A

13 Ai. Ctuit intertunter. inluslirlsai metallic. casing, said.; metalli@ eating. i991 d d a. pont Qfz at leasttene group Ctmslstingwf*S'eGfSIbQSGB; ,Calin Calif;2 ,CllOa Q13Bfr, CClaEz, and CCIE, a pair of insulating bushings," extending intogpposite eridsY o saidjmetallic casing, a

of saidbushings within the pool of theliquefied,` gaseous. fiuorine compound, a cooperable movable intermediate contact separable from` said stationary. contact to establisha, PlleSSure-generating arc, a cooperable second, movable., Contact, movable free of t'l1efp'o.ol, of the liqufledA gaseous iiuorine compound inl'tlxie: fully open-circuitposition, saidsecondmovabl Contactbeing4 cooperable with thewrnovable intermediate contact to establish an.` interruptingarc, interruptingmeans for forcingiiuid iiow from said pressure-generating arc towardl said finterruptin g arc toassisttin-effecting extinction of` the saine, saidjinterrupti'ng.v means being at` least partially supported;` from thelinner end of-` said-one bushing. withinjthe pool/, and said second` movable contact being slidable within the other of said bushings.

14. A circuit interrupter including a metallic casing, said metallic casing included a pool of at least one liqueed gaseous iluorine compound selected from the group consisting of SeF, SP6, SOF2, C2F6, C3128, ClOSF, CF3Br, CCIZFZ, and CClF3, a pair of insulating bushings extending into opposite ends of said metallic casing, a stationary contact carried adjacent the inner end of one of said bushings within the pool of the liquefied gaseous fluorine compound, a cooperable movable intermediate contact separable from said stationary contact to establish a pressure-generating arc, a cooperable second movable contact movable free of the pool of the liquefied gaseous iiuorine compound in the fully open-circuit position, said second movable contact being cooperable with the movable intermediate contact to establish an interrupting arc, means defining an interrupting orifice structure disposed adjacent said interrupting arc and wholly immersed Within the pool, means for forcing uid flow from said pressure-generating arc into said interrupting orifice structure to assist in effecting extinction of the interrupting arc, and said second movable contact being slidable within the other of said bushings.

l5. A fluid-blast circuit interrupter including contact means for establishing an arc, means defining an orifice structure adjacent said arc, operating means for actuating the contact means, compressed-huid reservoir means containing at least one liquefied gaseous fluorine compound selected from the group consisting of SeFS, SP6, SOF2, C2136, C3138, C1031?, CF3B1', CClzFZ, and CClFa, means for maintaining said liquid at a suiiicient driving pressure.

to enable it to be forced into the arc stream, said maintaining means including a different gaseous material under high pressure, conduit means interconnecting said compressed-fluid reservoir means with said arc, blast-valve means responsive to the opening operation of said operating means for releasing a blast of liquefied fluid through said orifice structure and into the arc through said conduit means to assist in effecting the extinction of the same, and a master control valve disposed in said conduit means responsive to the magnitude of the current being interrupted to control the amount of liquid passing through said conduit means, the master control valve functioning to permit more liquid to pass through said conduit means during heavy-current interruption than during lightcurrent interruption.

16. A fluid-blast circuit interrupter including a pair of ofN imeapaftessp .ed circuaerenilry aan t1, .lifss member., and, extending' fhrsashhe. sans ff-.Ja fesdeauidints ands d' am; enema circuit.` interruptterv including ay iiie'talli'c.` casing, saidl metalliccasinginehided a pool of.r at leastfone liqueestgvssoss flugtitacmttzundSelected frein the groan Consisting QSES, SOFa, CzFe,Cal'` CIOSE CQIZEMndJCClEa, a pair. `@il ins'ulatinabshings '@.Xtsd iris iatQ'ORPaSiLf@ erfdjsgf Saidmetallie Casilla a. Stafsnlaty. Contact carried adjacent theinner., end,ofqnelofsaidhbush. ings within the pool of the liqeiied gaseous iiuorine comf. pound, a cooperable movable intermediate contact lseparable frornsaidstationary contact tqestablishja pressuregenerating larc,acoop/era ble secondxmovablecontact movable free of the pool-fy the liquefied gaseous fluorine com- PQllDd intherfilllyopen-.circuit position, said secoridmovable Contact being cooperable with the movable intermediate contact to establish an interrupting arc, means for forcing iiuid flow from said pressure-generating arc toward said interrupting arc to assist in effecting extinction of the same, said second movable contact being slidable Within the other of said bushings, and a current transformer surrounding the said other bushing externally of the metallic casing.

18. A circuit interrupter including a metallic casing, said metallic casing included a pool of at least one liquefied gaseous iiuorine compound selected from the group consisting of SeF, SP6, SOF2, CZFG, C3F8, ClOSF, CFgBr, CC12F2, and CC1F3, a pair of insulating bushings extending into opposite ends of said metallic casing a stationary contact carried adjacent the inner end of one of said bushings within the pool of the liquefied gaseous ffuorine compound, a cooperable movable intermediate contact separable from said stationary contact to establish a pressuregenerating arc, means biasing said movable intermediate contact away from the stationary contact, a cooperable second movable contact movable free of the pool of the liquefied gaseous iluorine compound in the fully open-circuit position, said second movable contact being cooperable with the movable intermediate contact to establish an interrupting arc, means defining an interrupting orifice structure disposed adjacent said interrupting arc, means for forcing fluid flow from said pressure-generating arc into said interrupting orifice structure to assist in effecting extinction of the interrupting arc, and said second movable contact being slidable within the other of said bushings.

19. A Huid-blast circuit interrupter including Contact means for establishing an arc, means defining an orifice structure adjacent said arc, a manifold structure at least partially surrounding said orifice structure, operating means for actuating the contact means., compressed-fluid reservoir means containing at least one liquefied gaseous iiuorine compound selected from the group consisting of SeF, SFS, SOF2, CgFG, C3F8, CF3B1`, CC12F2, and CClF3, means for maintaining said liquid at a sufficient driving pressure to enable it to be forced into the arc stream, said maintaining means including a different gaseous material under high pressure, conduit means interconnecting said compressed-fluid reservoir means with said arc, blast-valve means responsive to the opening operation of said operating means for releasing a blast of liqueg ,an me: gemarteld; at

through said conduit means during heavy-current interrup-y tion than during light-current interruption.

20. A fluid-blast circuit interrupter including a'pairof separable contacts separable to establish an arc, an orice member associated with one of said contacts to direct uid 110W into the arc, means defining a manifold at least partially surrounding said orifice member, means providingan inlet opening to said manifold, means comprising compressed nitrogen gas for forcing at least one liquefied gaseous liuorine compound selected from the group con- Sisting Of SFG, SP6, SOF2, C2F6, C3F8, 01031:", CFaBl, CC12F2, and CClF3 through said inlet opening and into the manifold, a plurality of inlet apertures spaced circumferentially around said orifice member and extending through the same for feeding uid into the arc, and said inlet apertures in addition extending axially of said orifice member to disseminate the entrance ow of fluid into the arc stream.

References Cited in the le of this patent UNITED STATES PATENTS 901,967 Hewlett Oct. 27, 1908 201 Ball Oct. 6, Elseyr Apr. 3, McMahon Apr. 20, Marshall June 15, Trencham et al. Dec. 2l, Cooper Nov. 12, Cooper Nov. l2, vPrince Apr. l5, Sleats Oct. 7, Rankin Mar. 9, Jansson Dec. 13, Lingal et al. July 31, Eberhard et al. Nov. l2, Camilli et al. Sept. 23, Gratzmuller Aug. 18,

FOREIGN PATENTS France Feb. 9, France Dec. 10, Great Britain Oct. 7, Great Britain Aug. 23, Germany Oct. 10, Germany Nov. 9, Germany Jan. 10, Germany Feb. 19, Germany July 7, Sweden Sept. 10, 

1. A FLUID-BLAST CIRCUIT INTERRUPTER INCLUDING A PAIR OF SEPARABLE CONTATS SEPARABLE TO ESTABLISH AN ARC, AN ORIFICE MEMBER ASSOCIATED WITH ONE OF SAID CONTACTS TO DIRECT FLUID FLOW INTO THE ARC, MEANS DEFINING A MANIFOLD AT LEAST PARTIALLY SURROUNDING SAID ORIFICE MEMBER, MEANS PROVIDING AN INLET OPENING TO SAID MANIFOLD, MEANS FOR FORCING AT LEAST ONE LIQUIFIED GASEOUS FLUORINE COMPOUND SELECTED FROM THE GROUP CONSISTING OF SEF6, SF6, SOF2, C2F6, C3F8, CLO3, CF3BR, CCL2F2, AND CCLF3 THROUGH SAID INLET OPENING AND INTO THE MANIFOLD, A PLURALITY OF INLET APERTURES SPACED CIRCUMFERENTIALLY AROUND SAID ORIFICE MEMBER AND EXTENDING THROUGH THE SAME FOR FEEDING FLUID INTO THE ARC, AND SAID INLET APERTURES IN ADDITION EXTENDING AXIALLY OF SAID ORIFICE MEMBER TO DISSEMINATE THE ENTRANCE FLOW OF FLUID INTO THE ARC STREAM. 